Breakaway conductor pipe

ABSTRACT

A pair of semicylindrical conductor pipe sections are butted along their edges and releasably clamped around an upstanding well casing in a body of water. The clamped pipe sections can be released from a remote location, to fall away from the well casing and expose a portion of the latter for cutting and sealing in the event of well blow-out or fire.

[451 Nov. 21, 1972 United States Patent Sehoeffler Weber...........................61/54 ....24/284 X Pound [54] BREAKAWAY CONDUCTOR PIPE [72] Inventor:

2,412,185 12/1946 2,882,071 4/1959 K1ompar...........

Primary Examiner1-1enry T. Klinksiek Attorney-Bacon & Thomas [22] Filed:

211 App1.No.: 74,965

ABSTRACT A pair of semicylindrical conductor pipe sections are butted along their edges and rel around an upstandin The clamped pipe 137/375, 24/24, 24/270, 24/284, 138/155, 166/81, 166/242 easably clamped Int. g we" casing in a of water 137/375; 138/97, 99, 1 7, sections can be released from a 8 remote location, to fall away from the well casing and 166/75, 81, 242; 285/133 expose a portion of the latter for cutting and scaling in the event of well blow-out or fire.

[52] Field of Search 3 Claims, 3 Drawing Figures [56] References Cited UNITED STATES PATENTS 1,369,913 3/1921 Brunhoff.....................l66/81 PATENTED W21 I972 INVENTOR. WILL/HM N SCHOEFFLER BREAKAWAY CONDUCTOR PIPE 7 BACKGROUND OF THE INVENTION This invention relates to improvements in conductor pipes normally employed to isolate well casings from surrounding water in off-shore well installations.

It is customary, in off-shore oil well operations, wherein a well casing extends from the bottom of a body of water upwardly to the surface to a suitable artificial island or similar installation, to protect the well casing by surrounding the same with a conductor pipe, spaced outwardly therefrom, and it is common to fill the space between the well casing and the conductor pipe with concrete or the like. In the event of well blow-out or fire, it is desirable to be able to cut or seal the well casing to shut off well flow and thus prevent oil spillage into the surrounding water or loss of the product by fire.

This applicants copending application Ser. No. 38,654, filed May 19, l970, now US. Pat. 3,603,384, discloses and claims an apparatus for cutting and sealing such a well casing to thereby shut the well down. The apparatus disclosed in that copending application is capable of being applied to the well casing from a remote position and operative to perform its described function without the necessity of personnel approaching dangerously close to the well. However, the apparatus of that copending application is most economically constructed to be of a maximum capacity equal to the diameter of the largest well casing likely to be encountered. The addition of a conductor pipe around the well casing increases the diameter of the installation to such a large degree that it would be uneconomical to construct the apparatus of the copending application of sufficient size to encompass the conductor pipe.

SUMMARY OF THE INVENTION The present invention relates to a novel conductor pipe, as referred to heretofore, wherein at least a portion of the conductor pipe is formed of two separate semicylindrical halves that are clamped together around the well casing. A remotely operable clamp releasing means can be manipulated to release the clamps so that the two halves of the conductor pipe can fall away, thus exposing the smaller diameter well casing for cutting and sealing by the apparatus of the copending application referred to above. In the event the space between the well casing and conductor pipe is filled with concrete, the concrete filling is preferably so made that it, too, will fall away from the well casing when the conductor pipe sections are released.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a conductor pipe made according to the present invention and shown therein in full lines; the broken line illustration shows the conductor pipe sections after release and while DESCRIPTION OF A PREFERRED EMBODIMENT In the drawings numeral 2 indicates a well casing extending upwardly from the bottom of the body of water to the surface of the water (not shown). As shown in FIG. 1, a lower permanent conductor pipe portion 4 is shown surrounding a well casing 2 and above the upper portion 4 is a breakaway section of conductor pipe comprising two generally semicylindrical pipe sections 6 and 8. The sections 6 and 8, when butted together at their longitudinal edges 10 form a conductor pipe completely enclosing the well casing 2 in that region. The breakaway sections 6 and 8 rest on the lower conductor pipe section 4. It is to be understood, however, that in certain installations the lower portion 4 of the conductor pipe will be omitted and the entire conductor pipe may be of the breakaway sections to be described. Each pipe section 6 and 8 has a multiplicity of arcuate resilient bars 12 secured to its outer surface substantially midway between the abutting longitudinal edges 10. The bars 12 are secured to the pipe sections in a limited area, such as by welding as shown at 14, and each of the bars 12 normally assumes the position indicated in FIG. 3 wherein they are of larger radius than the outer surface of the conductor pipe sections 6 and 8. Thus, the free ends of the curved bars 12 are normally radially outwardly of the surface of the conductor pipe sections in the region of the abutting edges 10. As shown in FIG. 1, the multiplicity of such bars is secured to each pipe section, each corresponding in axial position to a like bar on the other pipe section.

As shown in FIGS. 2 and 3, a hook-ended lever 16 is pivoted adjacent each end of each bar 12, on a pivot axis 18. The adjacent or inner ends of the levers 16 are provided with hooks 20 thereon. In addition, each lever 16 is provided with an opening 22 which is aligned with a corresponding opening 24 in its bar 12 when the levers 16 are pivoted to the positions shown in FIG. 2 relative to the bars 12. When it is desired to install the breakaway conductor pipe of this invention about a well casing 2, the levers are swung to the positions shown in FIG. 2 and removable pins (not shown) are positioned in the aligned openings 22 and 24 to lock the levers 16 against pivotal movement. A loop or ring 26 is then engaged over each opposed pair of hooks 20 on one side of the conductor pipe and a toggle link clamp 27 is applied to each of the opposed pairs of hooks 20 on the other side of the conductor pipe in a manner to be described.

As shown in the drawings, the toggle clamp 27 comprises a pair of rings or loops 28 pivoted to a lever 30 on a spaced axes 32 near one end of the lever 30. The other end of the lever 30 is provided with an eyelet or loop 34 to which a suitable tension filament or cable 36 can be secured. After the loop 26 has been placed on the books on one side of the conductor pipe, the conductor pipe sections are drawn together so that the resilient end portions of the bars 12 adjacent the loop 26 are flexed inwardly against the outer surface of the conductor pipe sections 6 and 8. The loops 28 of the toggle clamp are than placed over the hooks 20 on the other side of the conductor pipe and by manipulating the lever 30 in a well known manner, to swing it to the position of FIG. 2, the loops 28 are effective to tightly clamp the other side of the conductor pipe sections in the position shown in FIG. 2. During this clamping the free ends of the resilient bars 12 adjacent thetoggle remote release. With the parts shown in the relative positions of F IG. 2, and the previously described pins removed, it will be obvious that the conductor pipe sections will remain in clamped position by virtue of the well known locking effect of the toggle clamps 27. In this condition the levers 16 cannot swing on their axis 18 and thus the hooks 20 securely hold the loops 26 and 28 in the illustrated locking positions.

in the vent of a blow-out or fire and when it is desired to release the breakaway sections to render the well casing easily accessible, the tension members, or cables 36, are tensioned and pulled in the direction of the arrow 38 of HS. 3, which effects release of the toggle lock 27. When the tension applied by toggle lock 27 is released, the ends of the resilient bars 12 are free to flex outwardly to the position of FIG. 3 and the tension in the loops 26 and 28 will effect pivotal movement of the levers 16 to the positions shown in FIG. 3, whereupon the loops 26 and toggle latches 27 are free to fall away and thus release the conductor pipe sections 6 and 8 so that they, too, can fall away from the well casing to expose the latter.

While a single specific embodiment of the invention 'has been shown and described herein, the same is ing:

a conductor pipe surrounding said well casing and at least a portion thereof comprising a pair of substantially semicylindrical separate pipe sections;

releasable clamping means holding opposite sides of said pipe sections together;

means operable from a remote location for releasing said clamping means whereby said pipe sections may separately fall away from said well casing to expose an upwardly extending portion thereof;

said clamping means including a toggle link clamp engaging adjacent pipe sections at one side of said conductor pipe and having a lever portion adapted to be swung laterally outwardly from said casing to a clamp-releasing position by a tension member extending therefrom to a laterally remote location; and

axially spaced loop means loosely engaging axially spaced first hooks on adjacent pipe sections at the other side of said conductor pipe whereby said loop means fali away from said hooks when said toggle clamp is released;

said toggle clamp including loop portions respectively engaging second hooks on adjacent pipe sections, said loop portions being pivoted to said lever portion on spaced axes. 2. A breakaway conductor pipe as defined in claim 1 wherein each of said first and second hooks is on an end of a hook lever pivotally mounted on resilient support means carried by said pipe sections and biased in a direction outwardly away from its pipe section, each book lever bearing against its pipe section when said clamping means are engaged but swingable about said axes to release said loops from said hooks when said toggle clamp is released and said support means move outwardly from said pipe sections.

3. A breakaway conductor pipe as defined in claim 2 including means for selectively and releasably locking said hook levers against pivoting on their supports. 

1. A breakaway conductor pipe for underwater wells having a well casing extending upwardly from the bottom of a body of water to the surface thereof, comprising: a conductor pipe surrounding said well casing and at least a portion thereof comprising a pair of substantially semicylindrical separate pipe sections; releasable clamping means holding opposite sides of said pipe sections together; means operable from a remote location for releasing said clamping means whereby said pipe sections may separately fall away from said well casing to expose an upwardly extending portion thereof; said clamping means including a toggle link clamp engaging adjacent pipe sections at one side of said conductor pipe and having a lever portion adapted to be swung laterally outwardly from said casing to a clamp-releasing position by a tension member extending therefrom to a laterally remote location; and axially spaced loop means loosely engaging axially spaced first hooks on adjacent pipe sections at the other side of said conductor pipe whereby said loop means fall away from said hooks when said toggle clamp is released; said toggle clamp including loop portions respectively engaging second hooks on adjacent pipe sections, said loop portions being pivoted to said lever portion on spaced axes.
 1. A breakaway conductor pipe for underwater wells having a well casing extending upwardly from the bottom of a body of water to the surface thereof, comprising: a conductor pipe surrounding said well casing and at least a portion thereof comprising a pair of substantially semicylindrical separate pipe sections; releasable clamping means holding opposite sides of said pipe sections together; means operable from a remote location for releasing said clamping means whereby said pipe sections may separately fall away from said well casing to expose an upwardly extending portion thereof; said clamping means including a toggle link clamp engaging adjacent pipe sections at one side of said conductor pipe and having a lever portion adapted to be swung laterally outwardly from said casing to a clamp-releasing position by a tension member extending therefrom to a laterally remote location; and axially spaced loop means loosely engaging axially spaced first hooks on adjacent pipe sections at the other side of said conductor pipe whereby said loop means fall away from said hooks when said toggle clamp is released; said toggle clamp including loop portions respectively engaging second hooks on adjacent pipe sections, said loop portions being pivoted to said lever portion on spaced axes.
 2. A breakaway conductor pipe as defined in claim 1 wherein each of said first and second hooks is on an end of a hook lever pivotally mounted on resilient support means carried by said pipe sections and biased in a direction outwardly away from its pipe section, each hook lever bearing against its pipe section when said clamping means are engaged but swingable about said axes to release said loops from said hooks when said toggle clamp is released and said support means move outwardly from said pipe sections. 